… on PHP level, which means they also will be serialized for single user on database level. If you change to store PHP sessions… transactional tables for session you can use GET_LOCK to get same behavior. In the start of the session you can do SELECT GET_LOCK(”,10) and in in the end of the request SELECT RELEASE_LOCK(”) where session_id is current session identifier. Note – setting this external lock…
Post: Worse than DDOS
August 18, 2008 By 5 Comments
… stages and just setting timeout is not enough. Beware of PHP sessions “files” handler I already wrote about this topic, but when… this all takes another angle. Default file handler means file gets locked while PHP request is being served. In this case because of… is our query if it is waiting on the session file lock we can get that file and use fuser to see what…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… http://bugs.mysql.com/bug.php?id=67647 Metadata locking behaves differently for queries that are…get piled up waiting for table metadata lock bringing down the MySQL server or causing all the connections to get… due to a different reason): session2 > set session lock_wait_timeout=1;CREATE TABLE t1(i …
Comment: PHP Sessions - Files vs Database Based
March 27, 2007 By 38 Comments
… my experience with an application design problem – when PHP issues locking select for the session right at the beginning and releases (if finishes… do the same, the situation I described occurs… then the session purgers kicks in, and I get called 
